The present invention is an apparatus for puncturing aerosol cans. More specifically it is an apparatus for puncturing aerosol cans and salvaging their content such that the cans"" contents can be disposed of in an environmentally safe manner and the cans can be reused when new valves are installed.
It has been recognized for a number of years that the contents of an aerosol can should be emptied from the can and disposed of in an environmental safe manner. There have been a number of patents with apparatus for doing so. For example, Hajms in U.S. Pat. No. 5,309,956, O""Neill in U.S. Pat. No. 5,395,982, Odasso in U.S. Pat. No. 3,333,735, and O""Brien, et al in U.S. Pat. No. 5,271,437 teach puncturing the bottom wall of the aerosol can. Others, such as Sato, et al in U.S. Pat. No. 5,086,814, Chipman, et al in U.S. Pat. No. 4,349,054, and Ceyba in U.S. Pat. No. 3,438,548 teach puncturing the lateral wall of the can. When either the lateral wall or the bottom wall of an aerosol can is pierced, the can cannot be reused but must be disposed of In year 2001, the cost of disposing of aerosol cans in bulk was approximately one dollar per can based on the cost of correctly disposing of a 55-gallon drum, which contains approximately 200 scrap aerosol cans.
In the present invention, the contents of a used aerosol can are removed through piercing the valve in the top surface of the can. With installation of a new valve, the can is suitable for reuse. In addition to the material conservation of the can, it is much less costly to install a new valve (approximately 6-8 cents per can) than to dispose of pierced aerosol cans in an acceptable way.
The invention has two main components:apparatus for puncturing an aerosol can and draining its contents through the puncture and apparatus for drawing any remaining contents from the can should there be insufficient pressure in the can for it to be fully evacuated when punctured. The puncturing apparatus has a stationary compartmented piercing tube and a housing that is free to move up and down relative to the piercing tube, assuming a vertical piercing tube. The housing is spring-loaded to offer resistance to movement so that a seal is achieved between the housing and the can before the piercing tube makes contact with the can, and to return the housing to its rest position after each piercing cycle. An air cylinder is used to apply pressure to the bottom of the aerosol can so that it will move downward to engage the piercing tube and release its contents into a first compartment. The piercing tube has ports in its lateral wall near the floor of the first compartment and the ceiling of a second compartment. This allows the contents of the aerosol to flow from the first compartment through a bypass chamber into the second compartment.
The second compartment of the piercing tube enters a cylinder, referred to as the drawing cylinder. The drawing cylinder contains a piston that divides it into two chambers, an upper chamber and a lower chamber. A piston rod is attached to a second air cylinder that is synchronized with the air cylinder that applies pressure to the aerosol can through a system of valves. Simultaneously with or slightly after starting to drain the contents of the aerosol, the second air cylinder causes the piston rod and piston to move downward to draw the contents of the aerosol can into the upper chamber through a vacuum effort. Then the direction of the piston is reversed and contents of the aerosol can are discharged from the upper chamber of the drawing cylinder through a port and check valve. The drawing cylinder and association synchronization apparatus are not needed if the aerosol can contains enough propellant to evacuate the aerosol can when pierced. Then, only the piercing apparatus is needed. However, to use the piercing apparatus without the drawing apparatus there is an additional step of pressure testing the aerosol can to ensure it contains sufficient propellant for the piercing apparatus to cause its complete evacuation.